I finally got a chance to connect each of the disks to another computer with an open SATA port. The first disk wasnt seen as another drive and In Windows Disk Management, showed all 232GB as unallocated. The other disk did show up as the E drive but would not open. In Windows Disk Management, 30GB was used, the other 202GB was unallocated.

So whatever the cause was, it destroyed the RAID 1 data drive from both disks and the RAID 0 system drive from one disk. Does that sound like something a buggy PSU might do? I wont know if the disks are still good until I format them and try it.

If a PSU isn't up to the load requirements, then drive motors will not spin at specified speed.. and cause write errors on hard drives. While the controller card isn't too fussy about exact-on voltages and current, the servo motors are! Read operations are not greatly affected, but if write operations are not properly choreographed, then file corruption can result in lost data.